America is warming up to the Republican tax cuts — and Democrats are starting to get worried.

Recent surveys have found growing support for the GOP overhaul of the tax code amid relentless messaging from Republicans and a barrage of businesses announcing bonuses and pay increases.

The momentum is increasingly leaving Democrats on the defensive on the kitchen-table economics they believe will be critical to victory in November's midterm elections. In an open memo this week, Democratic super PAC Priorities USA said the party's message has gotten drowned out in the debate over the tax plan.

"While Republican gains have not been enough to counter the extraordinary political environment for Democrats, it is imperative that Democrats return to focusing on the economic message and counter the narrative being pushed by the White House, Republicans in Congress and their special interest backers," the group said.

The super PAC pointed to internal poll numbers showing the percentage of voters who view President Donald Trump's tax policies favorably jumped from 32 percent late last year to 46 percent in February. Support for his economic policies also rose significantly, from 38 to 46 percent.

Still, the group said its analysis shows roughly half of voters would prefer to elect Democrats to serve as a check on the president rather than elect Republicans to help implement Trump's agenda.

"The most important and effective messages on Trump's economic policies for Democrats to focus on reinforce with voters the fact that Trump's economic policies will further enrich the wealthy and big corporations while hurting the middle class," the memo states.

Both parties are placing the tax plan at the heart of their campaign strategies. Democrats zeroed in on the $1.5 trillion price tag after the White House released its budget this week. Instead of paying for itself — as administration officials have repeatedly claimed — the tax cuts are driving deficits higher. Meanwhile, the Trump budget, which was released Monday, calls for dramatic reductions in spending on social services, including food stamps, federal student loans and Social Security Disability Insurance.

"The tax bill that was passed with only Republican votes last year was really a scam," Rep. John Yarmuth, D-Ky., ranking member of the budget committee, told CNBC. "It will increase the deficit, and this budget admits that."

But Democrats have also stumbled in their attempts to frame the law as primarily benefiting the wealthy and corporations — most notably, House Minority Leader Nancy Pelosi's characterization of bonuses for workers as "crumbs" compared with the benefits that businesses receive under the new tax code.

Republicans have seized on the comment as evidence that Democrats are out of touch with the working-class populism that has fueled Trump's popularity.

"I think only a very wealthy person from San Francisco would think that was a crumb," Mulvaney replied in a dig at Pelosi.

The conservative group Americans for Prosperity this week unveiled the first major installment of its $20 million campaign to tout the Republican tax plan. The group, which is backed by the billionaire industrialists Charles and David Koch, is spending $4 million on new ads targeting vulnerable Democratic Sens. Joe Donnelly in Indiana and Claire McCaskill in Missouri.

"Senator Joe Donnelly said he's support tax cuts for hard-working Hoosiers," one ad intones. "But when he had the chance, he said no."

Republicans are even turning Valentine's Day into a messaging opportunity. In a press release, House GOP leadership offered this refrain: